1) Field of the Invention
The field of this invention relates generally to resurfacing methods and more particularly to a new and improved method of recycling an asphalt surface such as a roadway or pavement.
2) Description of the Prior Art
Asphalt is widely used in the construction of highways and parking areas where large areas need to be covered with a relatively hard, flat, weather-resistant surface suitable for vehicular travel. With prolonged usage these asphalt surfaces develop cracks which permit the seepage of water therethrough to undermine the sand and rock subbase. Asphalt pavement includes a light oil that functions as a binder with the aggregate contained within the asphalt. The sun, as well as the amount of vehicular travel, causes this light oil to vaporize thereby causing the asphalt roadway to deteriorate. This deterioration of the asphalt surface necessitates reconditioning of that surface.
In the past it has been a common practice to recondition a worn asphalt surface by a hot application of a new mat of asphaltic material over the existing surface to form a new flat surface. This application of new material raises the general level of the asphalt surface by 1 inch to 11/2 inches. The problem with such an application of new material is that after a few years, and the surface has been reconditioned four or five times, the new surface is 5 inches to 9 inches higher than the old original surface. This raised surface level can be an especially serious problem, especially now where the roadway is at a higher level than the adjoining gutters or sidewalks. Each time a roadway is resurfaced by using overlay procedures reduces overhead room of underpasses. Where overlaying is done across bridges, each overlay applied to the bridge adds to the dead weight that the bridges must carry thereby diminishing the amount of vehicular weight that the bridge is able to carry with safety.
A more recent practice has been to recondition old asphalt surfaces by breaking up of the existing asphalt aggregate material, picking up the material for reconditioning, heating and then reapplying the heated reconditioned material as a new surface. The pavement is heated, scarified to a certain depth by a scarifying tool producing loose aggregate material. This loose aggregate material is then picked up, placed within a mixing vat where it is pulverized, combined with a light oil and then reapplied to the asphalt material.
This past method of recycling of the old asphalt has a disadvantage that it requires picking up of the old asphalt, moving it to a mixing location and then bringing it back and reapplying it to the roadway. It would substantially diminish the cost of resurfacing an asphalt roadway or pavement if this recycling procedure did not require the physical picking up of the loose aggregate material and transporting such to a mixer and then retransporting it back to be applied to the asphalt surface.